Patents by Inventor Subhash Balakrishna Pillai

Subhash Balakrishna Pillai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11816338
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Grant
    Filed: September 28, 2022
    Date of Patent: November 14, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yun-Tzuo Lai, Haining Liu, Subhash Balakrishna Pillai
  • Publication number: 20230017605
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Application
    Filed: September 28, 2022
    Publication date: January 19, 2023
    Applicant: Western Digital Technologies, Inc.
    Inventors: Yun-Tzuo LAI, Haining LIU, Subhash Balakrishna PILLAI
  • Patent number: 11500780
    Abstract: The subject technology provides for recovering a validity table for a data storage system. A set of logical addresses in a mapping table is partitioned into subsets of logical addresses. Each of the subsets of logical addresses is assigned to respective processor cores in the data storage system. Each of the processor cores is configured to check each logical address of the assigned subset of logical addresses in the mapping table for a valid physical address mapped to the logical address, for each valid physical address mapped to a logical address of the assigned subset of logical addresses, increment a validity count in a local validity table associated with a blockset of the non-volatile memory corresponding to the valid physical address, and update validity counts in a global validity table associated with respective blocksets of the non-volatile memory with the validity counts in the local validity table.
    Type: Grant
    Filed: October 30, 2020
    Date of Patent: November 15, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Caesar Cheuk-Chow Cheung, Haining Liu, Subhash Balakrishna Pillai
  • Patent number: 11487437
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Grant
    Filed: April 5, 2021
    Date of Patent: November 1, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Yun-Tzuo Lai, Haining Liu, Subhash Balakrishna Pillai
  • Patent number: 11474709
    Abstract: The subject technology provides for managing a data storage system. A host write command to write host data associated with a logical address to a non-volatile memory is received. A first physical address in the non-volatile memory mapped to the logical address in an address mapping table is determined. An indicator that the first physical address is bad checked. If the first physical address is indicated as bad, a valid count associated with a first set of physical addresses at a current value is maintained. The first set of physical addresses comprises the first physical address. If the first physical address is not indicated as bad, the first physical address is marked as invalid. The valid count associated with the first set of physical addresses is decremented.
    Type: Grant
    Filed: January 20, 2021
    Date of Patent: October 18, 2022
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kai-Lung Cheng, Yun-Tzuo Lai, Eugene Lisitsyn, Jerry Lo, Subhash Balakrishna Pillai
  • Publication number: 20210223965
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Application
    Filed: April 5, 2021
    Publication date: July 22, 2021
    Inventors: Yun-Tzuo LAI, Haining LIU, Subhash Balakrishna PILLAI
  • Patent number: 11048589
    Abstract: Host data segments are received and stored in a cached data unit corresponding to a previously stored data unit currently stored in non-volatile memory. Metadata is created that identifies unmodified previously stored segments of host data in the previously stored data unit that correspond to the received host data segments, the metadata including an update flag indicating that the previously stored data unit requires updating. In response to detecting the unexpected interruption of power, the cached data unit and the metadata is written to an area of the non-volatile memory array that is different than where the previously stored data unit is currently stored. Upon resuming operation following the unexpected interruption of power, the cached data unit is identified based on the update flag, as having been saved in response to the power shutdown without the previously stored data unit being updated in the non-volatile memory array, and then reloaded into the memory cache.
    Type: Grant
    Filed: April 17, 2019
    Date of Patent: June 29, 2021
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kai-Lung Cheng, Yun-Tzuo Lai, Eugene Lisitsyn, Jerry Lo, Subhash Balakrishna Pillai
  • Publication number: 20210141542
    Abstract: The subject technology provides for managing a data storage system. A host write command to write host data associated with a logical address to a non-volatile memory is received. A first physical address in the non-volatile memory mapped to the logical address in an address mapping table is determined. An indicator that the first physical address is bad checked. If the first physical address is indicated as bad, a valid count associated with a first set of physical addresses at a current value is maintained. The first set of physical addresses comprises the first physical address. If the first physical address is not indicated as bad, the first physical address is marked as invalid. The valid count associated with the first set of physical addresses is decremented.
    Type: Application
    Filed: January 20, 2021
    Publication date: May 13, 2021
    Inventors: Kai-Lung CHENG, Yun-Tzuo LAI, Eugene LISITSYN, Jerry LO, Subhash Balakrishna PILLAI
  • Patent number: 10990296
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Grant
    Filed: November 25, 2019
    Date of Patent: April 27, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES. INC.
    Inventors: Yun-Tzuo Lai, Haining Liu, Subhash Balakrishna Pillai
  • Publication number: 20210049106
    Abstract: The subject technology provides for recovering a validity table for a data storage system. A set of logical addresses in a mapping table is partitioned into subsets of logical addresses. Each of the subsets of logical addresses is assigned to respective processor cores in the data storage system. Each of the processor cores is configured to check each logical address of the assigned subset of logical addresses in the mapping table for a valid physical address mapped to the logical address, for each valid physical address mapped to a logical address of the assigned subset of logical addresses, increment a validity count in a local validity table associated with a blockset of the non-volatile memory corresponding to the valid physical address, and update validity counts in a global validity table associated with respective blocksets of the non-volatile memory with the validity counts in the local validity table.
    Type: Application
    Filed: October 30, 2020
    Publication date: February 18, 2021
    Inventors: Caesar Cheuk-Chow CHEUNG, Haining LIU, Subhash Balakrishna PILLAI
  • Patent number: 10901632
    Abstract: The subject technology provides for managing a data storage system. A host write command to write host data associated with a logical address to a non-volatile memory is received. A first physical address in the non-volatile memory mapped to the logical address in an address mapping table is determined. An indicator that the first physical address is bad checked. If the first physical address is indicated as bad, a valid count associated with a first set of physical addresses at a current value is maintained. The first set of physical addresses comprises the first physical address. If the first physical address is not indicated as bad, the first physical address is marked as invalid. The valid count associated with the first set of physical addresses is decremented.
    Type: Grant
    Filed: July 26, 2019
    Date of Patent: January 26, 2021
    Assignee: WESTERN DITIGAL TECHNOLOGIES, INC.
    Inventors: Kai-Lung Cheng, Yun-Tzuo Lai, Eugene Lisitsyn, Jerry Lo, Subhash Balakrishna Pillai
  • Patent number: 10846238
    Abstract: The subject technology provides for recovering a validity table for a data storage system. A set of logical addresses in a mapping table is partitioned into subsets of logical addresses. Each of the subsets of logical addresses is assigned to respective processor cores in the data storage system. Each of the processor cores is configured to check each logical address of the assigned subset of logical addresses in the mapping table for a valid physical address mapped to the logical address, for each valid physical address mapped to a logical address of the assigned subset of logical addresses, increment a validity count in a local validity table associated with a blockset of the non-volatile memory corresponding to the valid physical address, and update validity counts in a global validity table associated with respective blocksets of the non-volatile memory with the validity counts in the local validity table.
    Type: Grant
    Filed: June 27, 2019
    Date of Patent: November 24, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Caesar Cheuk-Chow Cheung, Haining Liu, Subhash Balakrishna Pillai
  • Publication number: 20200097187
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Application
    Filed: November 25, 2019
    Publication date: March 26, 2020
    Inventors: Yun-Tzuo LAI, Haining LIU, Subhash Balakrishna PILLAI
  • Patent number: 10503412
    Abstract: A data storage device that provides priority-based internal data movement includes a controller communicatively coupled to volatile memory and to non-volatile memory circuits, where the controller is configured to queue requests in a plurality of queues in the volatile memory, where each of the requests is associated with one of a plurality of internal data movement command types. The controller is also configured to select one of the plurality of queues based on a prioritization of the plurality of internal data movement command types. The controller is also configured to determine that the selected queue includes at least one request of the associated internal data movement command type. The controller is also configured to issue the at least one request from the selected queue to at least one of the non-volatile memory circuits.
    Type: Grant
    Filed: May 24, 2017
    Date of Patent: December 10, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yun-Tzuo Lai, Haining Liu, Subhash Balakrishna Pillai
  • Publication number: 20190347018
    Abstract: The subject technology provides for managing a data storage system. A host write command to write host data associated with a logical address to a non-volatile memory is received. A first physical address in the non-volatile memory mapped to the logical address in an address mapping table is determined. An indicator that the first physical address is bad checked. If the first physical address is indicated as bad, a valid count associated with a first set of physical addresses at a current value is maintained. The first set of physical addresses comprises the first physical address. If the first physical address is not indicated as bad, the first physical address is marked as invalid. The valid count associated with the first set of physical addresses is decremented.
    Type: Application
    Filed: July 26, 2019
    Publication date: November 14, 2019
    Inventors: Kai-Lung CHENG, Yun-Tzuo LAI, Eugene LISITSYN, Jerry LO, Subhash Balakrishna PILLAI
  • Publication number: 20190317700
    Abstract: The subject technology provides for recovering a validity table for a data storage system. A set of logical addresses in a mapping table is partitioned into subsets of logical addresses. Each of the subsets of logical addresses is assigned to respective processor cores in the data storage system. Each of the processor cores is configured to check each logical address of the assigned subset of logical addresses in the mapping table for a valid physical address mapped to the logical address, for each valid physical address mapped to a logical address of the assigned subset of logical addresses, increment a validity count in a local validity table associated with a blockset of the non-volatile memory corresponding to the valid physical address, and update validity counts in a global validity table associated with respective blocksets of the non-volatile memory with the validity counts in the local validity table.
    Type: Application
    Filed: June 27, 2019
    Publication date: October 17, 2019
    Inventors: Caesar Cheuk-Chow CHEUNG, Haining LIU, Subhash Balakrishna PILLAI
  • Publication number: 20190251028
    Abstract: Host data segments are received and stored in a cached data unit corresponding to a previously stored data unit currently stored in non-volatile memory. Metadata is created that identifies unmodified previously stored segments of host data in the previously stored data unit that correspond to the received host data segments, the metadata including an update flag indicating that the previously stored data unit requires updating. In response to detecting the unexpected interruption of power, the cached data unit and the metadata is written to an area of the non-volatile memory array that is different than where the previously stored data unit is currently stored. Upon resuming operation following the unexpected interruption of power, the cached data unit is identified based on the update flag, as having been saved in response to the power shutdown without the previously stored data unit being updated in the non-volatile memory array, and then reloaded into the memory cache.
    Type: Application
    Filed: April 17, 2019
    Publication date: August 15, 2019
    Inventors: Kai-Lung CHENG, Yun-Tzuo LAI, Eugene LISITSYN, Jerry LO, Subhash Balakrishna PILLAI
  • Patent number: 10380028
    Abstract: The subject technology provides for recovering a validity table for a data storage system. A set of logical addresses in a mapping table is partitioned into subsets of logical addresses. Each of the subsets of logical addresses is assigned to respective processor cores in the data storage system. Each of the processor cores is configured to check each logical address of the assigned subset of logical addresses in the mapping table for a valid physical address mapped to the logical address, for each valid physical address mapped to a logical address of the assigned subset of logical addresses, increment a validity count in a local validity table associated with a blockset of the non-volatile memory corresponding to the valid physical address, and update validity counts in a global validity table associated with respective blocksets of the non-volatile memory with the validity counts in the local validity table.
    Type: Grant
    Filed: December 30, 2016
    Date of Patent: August 13, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Caesar Cheuk-Chow Cheung, Haining Liu, Subhash Balakrishna Pillai
  • Patent number: 10379758
    Abstract: The subject technology provides for managing a data storage system. A host write command to write host data associated with a logical address to a non-volatile memory is received. A first physical address in the non-volatile memory mapped to the logical address in an address mapping table is determined. An indicator that the first physical address is bad checked. If the first physical address is indicated as bad, a valid count associated with a first set of physical addresses at a current value is maintained. The first set of physical addresses comprises the first physical address. If the first physical address is not indicated as bad, the first physical address is marked as invalid. The valid count associated with the first set of physical addresses is decremented.
    Type: Grant
    Filed: July 31, 2017
    Date of Patent: August 13, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Kai-Lung Cheng, Yun-Tzuo Lai, Eugene Lisitsyn, Jerry Lo, Subhash Balakrishna Pillai
  • Patent number: 10289551
    Abstract: Host data segments are received and stored in a cached data unit corresponding to a previously stored data unit currently stored in non-volatile memory. Metadata is created that identifies unmodified previously stored segments of host data in the previously stored data unit that correspond to the received host data segments, the metadata including an update flag indicating that the previously stored data unit requires updating. In response to detecting the unexpected interruption of power, the cached data unit and the metadata is written to an area of the non-volatile memory array that is different than where the previously stored data unit is currently stored. Upon resuming operation following the unexpected interruption of power, the cached data unit is identified based on the update flag, as having been saved in response to the power shutdown without the previously stored data unit being updated in the non-volatile memory array, and then reloaded into the memory cache.
    Type: Grant
    Filed: May 11, 2017
    Date of Patent: May 14, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Kai-Lung Cheng, Yun-Tzuo Lai, Eugene Lisitsyn, Jerry Lo, Subhash Balakrishna Pillai